In college? Time to line up next summer’s internship

FORTUNE — These days, landing a good job after graduation starts earlier than ever. “Your job hunt has to begin in your freshman year, with that first summer internship,” says Jason Levin, head of Washington, D.C., executive coaching firm Ready Set Launch. “Success as an intern is the No. 1 thing hiring managers look for.”

One way to find a place to shine next summer: Check out career site Vault.com’s latest list of top internships, which profiles the best places for students to gain real-world experience, ranked by factors like networking opportunities, training, and past interns’ satisfaction. The rankings also take into account great perks like free travel, housing, and gym memberships.

The top-rated programs accept only a very limited number of candidates, so it’s smart to cast a wide net and apply for as many internships as possible. Here’s where else to start looking:

Your school’s career services office. This might seem like a no-brainer, but a surprising number of students overlook it. “This should be your first stop,” says Deborah Federico, an undergraduate career counselor at Boston University’s School of Management. “Find out if they have either an online or print database of internships. Not only will the pool of applicants be relatively small, compared to internship search sites, but the companies posting openings are there because they want to find someone from your school.”

Online internship databases. One of Federico’s favorites is Simply Hired, because it lets aspiring interns search by geographical location. “You can also set up multiple searches, get daily email alerts with any internship that matches your search criteria, or sort your search by company name to zero in on internships at your favorite companies,” she says.

Craigslist. “Yes, Craiglist!,” says Federico. “Despite the many sketchy posts on the site, lots of my students have found very good internships there, particularly at smaller companies.”

Your network of friends and relatives. “Many of my students have found great internships through neighbors, aunts, uncles, cousins, and best friends’ parents,” Federico says. Start by talking with them, and then branch out into contacting alumni of your college.

Target companies. If there’s a particular company where you’d like to work, take a look at its career page, where internships might be listed. “If nothing seems to be available right now, send a resume and a cover letter expressing interest in potential future openings,” Federico suggests. “Then follow up with human resources. You could even consider designing your own internship. Employers will love your initiative, and most companies would welcome an extra pair of hands during the summer.”

What if you try all that and strike out — or if you just can’t afford to spend the summer on an unpaid gig (as most internships are)? All is not lost. “Eight out of ten employers who review resumes of new college grads are looking for evidence of leadership skills,” notes Andrea Koncz, employment information manager at the National Association of Colleges and Employers. “In addition, 75% of hiring managers are looking for problem-solving skills.”

So, in the absence of an internship, try to find ways to get experience with either or both. “Spending the summer as a lifeguard is fine,” says Jason Levin. “Managing a team of lifeguards is even better. The point is to show that you can take responsibility for something beyond the classroom.”

Levin also recommends seeking out ways to contribute to a faculty-supervised research or consulting project during the school year. “At most universities, there are plenty of joint efforts between professors and businesses that you can get involved in, as well as student-run organizations on campuses that do assignments for companies,” he says. “Ask your campus career center or student activities office for information on these.

“Or you can find opportunities through national fraternities focused on business, like Delta Sigma Pi,” Levin adds. Founded at New York University in 1907, Delta Sigma Pi (open to both men and women) now has 300 chapters with about 226,000 members. One of them may well be able to hook you up with part-time work that will catch a future employer’s eye.